Conventional technologies for capturing an appearance and an expression of a face are classified into two main categories. In the first method, information regarding a static appearance of a face is scanned using an active sensor such as a laser and a pattern ray, markers are attached to portions of the face such as the eyes, the mouth and the cheeks of the face, where main changes in an expression of the face occur, a motion of the face is captured by tracing the markers, and a face animation is created by manually combining the two pieces of information by designers.
Actually, the method is widely utilized to obtain special effects of high quality in image contents such as a movie and a commercial film. However, the method requires manual operations of skilled designers and artists to combine the information obtained by different type of sensors, and is time-consuming in creating a model. On the other hand, the method enables easy creation of a new face animation or easy edition and correction of an animation once a face model is created.
Another technology for capturing an appearance and an expression of a face includes functions for simultaneously capturing information regarding an appearance shape of a face and information regarding an expression of the face. Representative technologies of this type include a space-time stereo method in which an existing 3D scanner technology is expanded to capture the shape of a face that changes with time and an approach method using a MOVA system in which special make-up is applied to a face and information regarding the geometric shape of a face that changes with time and texture information are simultaneously extracted by mounting a special filter to a camera to recognize the special make-up. These methods enables capture of information regarding an expression of a face that changes with time, but require well-controlled illumination environments and photographing conditions.
As mentioned above, the conventional technologies for capturing the appearance and expression of a face require many manual operations of skilled designers and artists and need well-controlled illumination environments and photographing conditions when information is obtained by capturing the expression of the face.